The time requirement to solo depends on various factors. The type of things to consider are what type of airplane are you learning in? Is it a technically advanced aircraft (TAA)? Also what type of airspace are you training in and around? How experienced is the instructor? How often are you flying? Learning to fly safely by yourself, handle the radios at a busy airport, and manage a GPS, autopilot, nav/comms is much more challenging than the stories ol' man hoppin in the J-3 after 3 hours of dual. J-3's dont even have flaps!

Congrats on the solo, hope this helps anyone else in the same situation